diff -ruN ../base/src/backend/utils/sort/tuplesort.c src/backend/utils/sort/tuplesort.c
--- ../base/src/backend/utils/sort/tuplesort.c	2003-08-17 21:58:06.000000000 +0200
+++ src/backend/utils/sort/tuplesort.c	2003-09-05 10:04:22.000000000 +0200
@@ -2071,6 +2071,33 @@
 				(errcode(ERRCODE_UNIQUE_VIOLATION),
 				 errmsg("could not create unique index"),
 				 errdetail("Table contains duplicated values.")));
+	else
+	{
+		/*
+		 * If key values are equal, we sort on ItemPointer.  This might help
+		 * for some bad qsort implementation having performance problems
+		 * with many equal items.  OTOH I wouldn't trust such a weak qsort
+		 * to handle pre-sorted sequences very well ...
+		 *
+		 * Anyway, this code doesn't hurt much, and it helps produce indices
+		 * with better index correlation which is a good thing per se.
+		 */
+		ItemPointer tid1 = &tuple1->t_tid;
+		ItemPointer tid2 = &tuple2->t_tid;
+		BlockNumber blk1 = ItemPointerGetBlockNumber(tid1);
+		BlockNumber blk2 = ItemPointerGetBlockNumber(tid2);
+		
+		if (blk1 != blk2)
+			return (blk1 < blk2) ? -1 : 1;
+		else
+		{
+			OffsetNumber pos1 = ItemPointerGetOffsetNumber(tid1);
+			OffsetNumber pos2 = ItemPointerGetOffsetNumber(tid2);
+			
+			if (pos1 != pos2)
+				return (pos1 < pos2) ? -1 : 1;
+		}
+	}
 
 	return 0;
 }